Hot-air pipe



(No Model.) I

A. MILLER.

HOT AIR PIPE. No. 490,579'. Patented Jan. 24, 189.3.

fr minimi llllilllm I li l nnte.

AUGUST MILLER, OE BURLINGTON, IOWA.

HOT-Al R PIPE.

SPECIFICATION forming part of Letters Patent No. 490,579, dated January24, 1893.

Application tiled J' une 15, 1892. Serial No. 436,844. (No model.)

To all whom it may concern,.-

Be it known that I, AUGUST MILLER, a citizen of the United States,residing at Burlington, in the county of Des Moines and State of Iowa,have invented certain new and useful Improvements in Hot-Air Pipes; andI do hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

Figure l, isa perspective view of this invention. Fig. 2, is a centralvertical cross section of Fig. l,the parts of the pipe in position oneupon the other but not pressed together. Fig. 3, is a side elevation ofouter wall of the pipe. Fig. il, a side elevation of the inner wall ofthe pipe. Fig. 5, isa detail in section showing the two sections orparts pressed together as in Fig. l. Fig. 6, is a detail showing moreplainly the relative structure of the inner and outer pipes.

This invention is an improvement in that class which relates to doublepipes to be located in partitions for the transmission of hot air, inwhich the several sections consist of an internal and external shellhaving a space between them for cold air circulation to prevent hot airfrom coming into contact with wood or other ignitible substance throughwhich the pipe passes. These double pipes are made in sections andconnected together by slipping the end of one section into the end ofthe next section, and then tacking or soldering them together. By myinvention each section of the hollow pipe is so made as to be adaptedeasily to the next one, while at the saine time the walls are so bracedas to hold their shape, and yct not interfere with the transmission ofcold air current between the walls.

In the drawings A, denotes the external Wall or pipe, and B, theinternal wall or pipe and C, the cold air space between them. At the topeach of the double walls has a bead or turned over edge At the bottom orlower end each pipeA and B, is entirely open and unobstructed. At eachcorner the pipes are cut out or slit as at o., and b, respectively toallow easy expansion or contraction; thus the ends of the pipes have abeveled edge, the beveling being toward each other so that the openingbetween the pipes is larger than the opening at the bottoms. It ispreferable to have each joint or section of each pipe of the samelength. At the top of each section is inserted at the sides yand endsbetween the double wall a connecslots or openings CZ, for the freeupward circulation of cold air, while at the ends of each, is leftquitea large opening` d', of which there will be one at each corner ofthe double pipe. The apex of the bent connection D, may extend slightlyabove the top of the section of the double pipe, but whether so placed,or placed on a level with the top, or just below the same it willconstitute also a guide for each of the lower open ends of the nextsection when it is applied, as in building up or forming an entire pipe;also acts as a division strengthening piece. Having now two sections ofpipe, one is placed upon and into the other, the beveled edges a, and b,of the one section striking upon the sloping part of the connection D,between the two walls ot' the pipe, thus insuring an easyjoining of thetwo sections. As now the two sections are put together, the end of oneis pushed down into the other, and this causes the beveled edges of theinner and outer pipes to separate and slide down upon the slantingportion of the connection between the two pipes and into the lower partof that connection where it tits very tightly, and thus the joint ismade complete; if desired it may also be tacked or soldered. Anotherjoint is laid upon the up'- per of the two already put together andsuitably secured thereto, and so the process is continued until asmanyjoints as desired are added.

It should be further stated that by beveling the lower ends a, and b, asabove described neither will strike the outer edges of the section uponwhich, when two parts or sections of the pipe are being broughttogether, they impinge but willvcertainly strike upon the sloping sidesot' the V-shaped connection. Thus when these beveled ends strike theinclined surfaces of the said connection they can easily be forced downinto IOO the socket formed by bends of said connection as shown in Figs.5 and 6. When these beveled ends are thus shoved or pressed down to thebottom of said socket or cavity they will tit very tightly in place,chiey by reason of friction and thus the two sections of pipe will beheld tight and close together.

One very considerable advantage of this pipe is that in case a part ofone section or joint only is desired, the lower part can be cut oit, theedges then can be readily beveled, and at once it is ready to be putupon the corresponding section of another pipe. Thus the section may beas long or as short as desired. The sections may be built of uniformlength in a shop, and then when put into a building out to any desiredlength. This is a decided advantage over anything I know of now in use,as by the old method a Special joint must be built where a short portiononly is desired.

In the detail of manufacturing this pipe I do not propose to limitmyself to a square shape of the external or internal pipe; and in thestructure and arrangement of the perforated division and guide strips,it is not necessary to confine myself to the exact representation nowgiven.

Thile I have used the descriptive words of top and bottom for eachsection, it is evident that the inversion of each section would make.

no essential dilerence in the structure or operation of this invention.

Having now described my invention what I claim is:

l. A double-walled pipe for the transmission of hot air, made insections, each having at one end a perforated connection between the twowalls, and each of said walls at the lower end being open, and alsoslitted or cut out at the corners, as and for the purpose set forth.

2. In combination with the doubled walled ho't air pipe made insections, each section having beveled edges, as described, the V- shapedand perforated strips in each section adapted to receive the saidbeveled edges of the adjacent section, said beveled edges acting byfriction chiefiy to hold the two sections together.

3. A double walled hot air pipe each section of which has its lower endsslitt'ed or cut out, and at its upper endsjs provided between the wallswith perforated guide pieces, substantially as set forth.

In testimony whereof I affix my signature in presence of two witnesses.

AUGUST MILLER.

Witnesses:

CHR. REICHERT, OHAS. C. CLARK.

